1. Field of the Invention
The present invention relates to an electric vehicle including driven wheels which are connected to and driven by an electric motor using a battery as an energy source and which driven wheels are capable of being liquid-pressure braked and regeneratively braked.
2. Description of the Prior Art
Such an electric vehicle described in Japanese Patent Application Laid-Open No. 28933/74 is conventionally known. With that electric vehicle, the recovery of energy by a regenerative braking by the electric motor can be preferentially performed to possibly charge the battery, and after the magnitude of the regenerative braking force has reached a limit, a liquid pressure braking can be additionally used, thereby insuring a sufficient braking force.
The regenerative braking force generateable by the electric motor is varied depending upon the number of revolutions of the motor and, in a lower rotational range, it is difficult to generate the regenerative braking force. When the battery is in a fully charged state, it may be necessary in some cases not to conduct the regenerative braking in order to prevent damage to the battery due to over-charging. Therefore, if the regenerative braking is impossible, as described above, when the driven wheels are being regeneratively braked under a condition in which a liquid pressure circuit connecting the master cylinder and a brake caliper has been cut off to inhibit the liquid pressure braking, it is necessary to open the liquid pressure circuit to switch over the regenerative braking to the liquid pressure braking.
When the liquid pressure circuit has been opened to switch over the regenerative braking to the liquid pressure braking, the liquid pressure hitherto cut off is suddenly transferred from the master cylinder to the brake caliper. As a result, the stroke of the brake pedal is changed at that moment by a distance corresponding to the amount of liquid consumed in the brake caliper. Such a large variation in brake pedal stroke results in a problem of a degraded braking feeling.